This invention relates generally to the field of systems, methods, or devices used to secure, stabilize or anchor manufactured homes to the ground after the homes have been transported to the building site and mounted onto support piers. More particularly, the invention relates to such systems, methods or devices which utilize metal tie down straps connected to ground anchors.
Manufactured homes are produced at factories and then transported to sales centers and final building sites for assembly and use. The overall size of the transportable units are limited by transportation considerations, in that they cannot exceed certain maximum dimensions for travel over roadways. It is thus very common to provide for manufactured homes which are built in separate components or units which can be individually transported to the sites and then assembled. Such homes are often referred to as double wide home, since it is very common to provide two longitudinally extensive units which are joined lengthwise to form the larger finished home. The units are constructed on two parallel chassis I-beams, the I-beams providing longitudinal support and allowing for the attachment of wheels to the units for transport. The I-beams remain exposed beneath the floor of the home. At the assembly or use site, the I-beams are usually supported by a large number of spaced support piers or columns, constructed of concrete blocks with wedge-shaped wooden inserts to provide for the proper support height beneath the I-beam at each location.
Because the manufactured homes are to be transported, excessive weight cannot be tolerated, and so manufacturing considerations stress strong but light materials for construction. This fact, along with the fact that they are positioned several feet above ground level, means that the homes are very susceptible to adverse effects of high winds, especially if the area below the structure is not covered. Therefore, federal and local codes and standards related to manufactured homes require that the homes be provided with an anchoring system to stabilize the home against wind load effects. The most commonly utilized system involves a large number of metal straps which are secured to the frames, trusses or I-beams of the manufactured homes and then to ground anchors embedded into the ground around and beneath the home. A major problem with these systems is that the fixation and retention of the ground anchors, which usually comprise a shaft with helical plates which is rotated into the ground, is highly dependent on the type and density of the soil as well as the particular angle of insertion relative to the tensile load. Under high wind loads, movement of the anchors or actual bending of the upper portion of the anchor is not uncommon, resulting in loss of stabilization of the manufactured home. The home may shift horizontally or vertically relative to the support piers, which can cause damage or complete destruction of the home.
An example of an improved stabilization system for manufactured housing is shown in U.S. Pat. No. 5,697,191 to MacKarvich. Straps are connected in a crossing manner from the I-beams to ground anchors, and stabilizing plates extend between adjacent support piers and from the support piers to the ground anchors, thus maintaining the ground anchors in a spaced relation to prevent movement of the anchors in a direction which would loosen the straps. This system continues to utilize helical anchors placed into the ground, and does not provide any means to directly counter movement in the longitudinal direction.
It is an object of this invention to provide a system and method for securing, stabilizing and anchoring a manufactured home which effectively precludes movement in all directions, horizontal and vertical, when placed under wind load forces. It is an object to provide such a system and method which utilize standard metal straps and embedded anchors which receive the straps, such that the system can be assembled easily and quickly without recourse to special equipment. It is an object to provide the system and method where the straps are connected directly to the I-beams supporting the manufactured housing units. It is an object to provide such a system and method where lateral and longitudinal movement is less than one half inch at 150% of the design load.